Not sure if this is where to ask, but I have a 24V MotorGuide on my Tracker and I'm thinking of going to a glass boat. The few that I've looked at come equipped with 12V trolling motors and that got me wondering if that isn't a little underpowered for an 18ft. boat?  I like the 24V more for the amount of fishing time I can get before I have to recharge rather than the thrust it offers over the 12V.  I read of guys that have 36V motors on their 21ft. boats. That's what got me to wondering about a 12V on an 18ft.

 

My 18' and 22' boats are both 24v, 80 lb. motors.

I have had a 17 foot glass boat with a 12 volt, 50 pound thrust motor for over 25 years. I wasn't setting any speed records but it worked well enough. I just upgraded to an 80 pound Terrova. I do have to add that my glass boat weighs a lot less than most aluminum boats built today. 

I use a 36V 105# on my 16' Tracker.

There is no such thing as too much trolling motor power.

In wind and current there is such a thing as too little trolling motor power.

Hey Joe.

My 18'-6" boat that I had on the roadtrip last year had a 24v motor on it.

Thrust rating is pretty straightforward as to how it equates to moving a boat on the water.

 

What is the significance and/or difference of voltage rating as it relates to trolling motors?

12v = 1 battery

24v = 2 battery

36v = 3 battery

Thrust is a fairly forward. Amp. draw as it relates to thrust is where my concern lies. It's kind of like the mpg you get from your truck but in reverse. A small block will get better fuel mileage at a given speed than a big block. You'll get more time out of a 24V than a 12V running at the same thrust, Not because the 24V draws less amps (it may), but because of the two batteries it's drawing them from.

Thrust is a fairly forward. Amp. draw as it relates to thrust is where my concern lies. It's kind of like the mpg you get from your truck but in reverse. A small block will get better fuel mileage at a given speed than a big block. You'll get more time out of a 24V than a 12V running at the same thrust, Not because the 24V draws less amps (it may), but because of the two batteries it's drawing them from.

At the same output power (thrust) a 24V motor uses 1/2 the amps as a 12V motor. A 36V motor would use 1/3 the amps.

Ditch the 12v. Better to have it and not need it than need it and not have it. 

The 24v is way better than a 12v. Oh yes you have to buy 2 batteries but you get many benefits.  You get more power and longer power.  You never draw the batteries down like you can with a 12v system.  Your batteries should last longer.

Go for at least the 24V on the 18 footer. I think you'll be disappointed with the 12V.